Zoom lens and imaging apparatus

ABSTRACT

An object of the present invention is to provide a zoom lens that can perform favorable correction of chromatic aberration in the entire zoom range, and can have higher performance and a smaller size than conventional ones; and an imaging apparatus including the zoom lens. To achieve the object, provided are a zoom lens and an imaging apparatus including the zoom lens. The zoom lens includes, in order from an object side: a positive first lens group G1; a negative second lens group G2; and a GR group including one or more lens groups. In the zoom lens, changing focal length is performed by varying intervals between the lens groups. The GR group includes convex lenses GpH and GpL satisfying predetermined conditional expressions. The convex lens GpH is the positive lens which is arranged second position or after from the object side in positive lenses in the GR group.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to Japanese Patent Application No.2017-153069 filed Aug. 8, 2017, the disclosure of which is herebyincorporated in its entirety by reference.

BACKGROUND OF THE INVENTION Field of the Invention

This invention relates to a zoom lens suitable for imaging opticalsystems, such as film cameras, video cameras, and digital still cameras,and an imaging apparatus including the zoom lens.

Description of the Related Art

An imaging apparatus using a solid-state imaging device, such as adigital camera or a video camera, has been widely used. As pixel densityin the solid-state imaging device increases, a higher performance hasbeen required for imaging optical systems used in imaging apparatuses.In addition, with reductions in the sizes of imaging apparatuses,reductions in the sizes of imaging optical systems have been required.

For interchangeable lens imaging apparatuses, such as single-lens reflexcameras, zoom lens that adjust the focal length according to thedistance to an object to change an image viewing angle are widely used.

For example, Japanese Patent Laid-Open No. 2015-55858 disclosesso-called standard large-aperture zoom lens for SLRs. The zoom lensdisclosed in Japanese Patent Laid-Open No. 2015-55858 consists of, inorder from the object side, a first lens group having positiverefractive power, a second lens group having negative refractive power,and the rear lens group including one or more lens groups. In the zoomlens, a positive lens, which is made of glass and has a low-refractiveindex, a low-dispersion, and a positive extraordinary dispersion, isarranged in the first lens group having positive refractive power,thereby suppressing variations in chromatic aberration during zooming.However, in the zoom lens, variations in chromatic aberration duringzooming are not adequately suppressed; therefore, a further increase inperformance is required in the entire zoom range.

SUMMARY OF THE INVENTION

Accordingly, an object of the present invention is to provide alarge-aperture zoom lens that can perform favorable correction ofchromatic aberration in the entire zoom range, and an imaging apparatusincluding the zoom lens.

To solve the above problems, a zoom lens according to the presentinvention includes, in order from an object side: a first lens grouphaving positive refractive power; a second lens group having negativerefractive power; and a GR group including one or more lens groups,changing focal length is performed by varying intervals between the lensgroups. The GR group includes one or more convex lens GpH satisfying thefollowing conditional expression (1), and one or more convex lens GpLsatisfying the following conditional expression (2). The convex lens GpHis the positive lens which is arranged second position or after from theobject side in positive lenses in the GR group.1.85<ndpH<2.50  (1)60.0<vdpL<100.0  (2)Here,ndpH is the refractive index related to the d-line of the convex lensGpH, andvdpL is the Abbe constant related to the d-line of the convex lens GpL.

To solve the aforementioned problem, an imaging apparatus of the presentinvention includes the zoom lens and an imaging device that is arrangedon the image side of the zoom lens and converts an optical image formedby the zoom lens to electrical signals.

The present invention can provide a large-aperture zoom lens that canperform favorable correction of chromatic aberration in the entire zoomrange, and an imaging apparatus including the zoom lens.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of a lens configuration example of azoom lens of Example 1 of the present invention at a time of focusing toinfinity at the wide angle end;

FIG. 2 shows a spherical aberration diagram, an astigmatism diagram, anda distortion aberration diagram of the zoom lens of Example 1 at a timeof focusing to infinity at the wide angle end;

FIG. 3 shows a spherical aberration diagram, an astigmatism diagram, anda distortion aberration diagram of the zoom lens of Example 1 at a timeof focusing to infinity at an intermediate focal length;

FIG. 4 shows a spherical aberration diagram, an astigmatism diagram, anda distortion aberration diagram of the zoom lens of Example 1 at a timeof focusing to infinity at the telephoto end;

FIG. 5 is a cross-sectional view of a lens configuration example of azoom lens of Example 2 of the present invention at a time of focusing toinfinity at the wide angle end;

FIG. 6 shows a spherical aberration diagram, an astigmatism diagram, anda distortion aberration diagram of the zoom lens of Example 2 at a timeof focusing to infinity at the wide angle end;

FIG. 7 shows a spherical aberration diagram, an astigmatism diagram, anda distortion aberration diagram of the zoom lens of Example 2 at a timeof focusing to infinity at an intermediate focal length;

FIG. 8 shows a spherical aberration diagram, an astigmatism diagram, anda distortion aberration diagram of the zoom lens of Example 2 at a timeof focusing to infinity at the telephoto end;

FIG. 9 is a cross-sectional view of a lens configuration example of azoom lens of Example 3 of the present invention at a time of focusing toinfinity at the wide angle end;

FIG. 10 shows a spherical aberration diagram, an astigmatism diagram,and a distortion aberration diagram of the zoom lens of Example 3 at atime of focusing to infinity at the wide angle end;

FIG. 11 shows a spherical aberration diagram, an astigmatism diagram,and a distortion aberration diagram of the zoom lens of Example 3 at atime of focusing to infinity at an intermediate focal length;

FIG. 12 shows a spherical aberration diagram, an astigmatism diagram,and a distortion aberration diagram of the zoom lens of Example 3 at atime of focusing to infinity at the telephoto end;

FIG. 13 is a cross-sectional view of a lens configuration example of azoom lens of Example 4 of the present invention at a time of focusing toinfinity at the wide angle end;

FIG. 14 shows a spherical aberration diagram, an astigmatism diagram,and a distortion aberration diagram of the zoom lens of Example 4 at atime of focusing to infinity at the wide angle end;

FIG. 15 shows a spherical aberration diagram, an astigmatism diagram,and a distortion aberration diagram of the zoom lens of Example 4 at atime of focusing to infinity at an intermediate focal length;

FIG. 16 shows a spherical aberration diagram, an astigmatism diagram,and a distortion aberration diagram of the zoom lens of Example 4 at atime of focusing to infinity at the telephoto end;

FIG. 17 is a cross-sectional view of a lens configuration example of azoom lens of Example 5 of the present invention at a time of focusing toinfinity at the wide angle end;

FIG. 18 shows a spherical aberration diagram, an astigmatism diagram,and a distortion aberration diagram of the zoom lens of Example 5 at atime of focusing to infinity at the wide angle end;

FIG. 19 shows a spherical aberration diagram, an astigmatism diagram,and a distortion aberration diagram of the zoom lens of Example 5 at atime of focusing to infinity at an intermediate focal length;

FIG. 20 shows a spherical aberration diagram, an astigmatism diagram,and a distortion aberration diagram of the zoom lens of Example 5 at atime of focusing to infinity at the telephoto end;

FIG. 21 is a cross-sectional view of a lens configuration example of azoom lens of Example 6 of the present invention at a time of focusing toinfinity at the wide angle end;

FIG. 22 shows a spherical aberration diagram, an astigmatism diagram,and a distortion aberration diagram of the zoom lens of Example 6 at atime of focusing to infinity at the wide angle end;

FIG. 23 shows a spherical aberration diagram, an astigmatism diagram,and a distortion aberration diagram of the zoom lens of Example 6 at atime of focusing to infinity at an intermediate focal length;

FIG. 24 shows a spherical aberration diagram, an astigmatism diagram,and a distortion aberration diagram of the zoom lens of Example 6 at atime of focusing to infinity at the telephoto end;

FIG. 25 is a cross-sectional view of a lens configuration example of azoom lens of Example 7 of the present invention at a time of focusing toinfinity at the wide angle end;

FIG. 26 shows a spherical aberration diagram, an astigmatism diagram,and a distortion aberration diagram of the zoom lens of Example 7 at atime of focusing to infinity at the wide angle end;

FIG. 27 shows a spherical aberration diagram, an astigmatism diagram,and a distortion aberration diagram of the zoom lens of Example 7 at atime of focusing to infinity at an intermediate focal length;

FIG. 28 shows a spherical aberration diagram, an astigmatism diagram,and a distortion aberration diagram of the zoom lens of Example 7 at atime of focusing to infinity at the telephoto end;

FIG. 29 is a cross-sectional view of a lens configuration example of azoom lens of Example 8 of the present invention at a time of focusing toinfinity at the wide angle end;

FIG. 30 shows a spherical aberration diagram, an astigmatism diagram,and a distortion aberration diagram of the zoom lens of Example 8 at atime of focusing to infinity at the wide angle end;

FIG. 31 shows a spherical aberration diagram, an astigmatism diagram,and a distortion aberration diagram of the zoom lens of Example 8 at atime of focusing to infinity at an intermediate focal length;

FIG. 32 shows a spherical aberration diagram, an astigmatism diagram,and a distortion aberration diagram of the zoom lens of Example 8 at atime of focusing to infinity at the telephoto end;

FIG. 33 is a cross-sectional view of a lens configuration example of azoom lens of Example 9 of the present invention at a time of focusing toinfinity at the wide angle end;

FIG. 34 shows a spherical aberration diagram, an astigmatism diagram,and a distortion aberration diagram of the zoom lens of Example 9 at atime of focusing to infinity at the wide angle end;

FIG. 35 shows a spherical aberration diagram, an astigmatism diagram,and a distortion aberration diagram of the zoom lens of Example 9 at atime of focusing to infinity at an intermediate focal length;

FIG. 36 shows a spherical aberration diagram, an astigmatism diagram,and a distortion aberration diagram of the zoom lens of Example 9 at atime of focusing to infinity at the telephoto end.

As for the reference numerals used in the aforementioned drawings, G1represents the first lens group, G2 represents the second lens group, G3represents the third lens group, G4 represents the fourth lens group, G5represents the fifth lens group, G6 represents the sixth lens group, Srepresents an aperture stop, and I represents an image plane.

DESCRIPTION OF THE INVENTION

Embodiments of a zoom lens and imaging apparatus according to thepresent invention will now be described. Note that the zoom lens and theimaging apparatus described below are merely one aspect of the zoom lensand imaging apparatus according to the present invention, and the zoomlens and imaging apparatus according to the present invention are notlimited to the following aspect.

1. Zoom Lens

1-1. Configuration of Zoom Lens

An embodiment of a zoom lens according to the present invention will befirst described. The zoom lens of this embodiment includes, in orderfrom the object side, a first lens group having positive refractivepower, a second lens group having negative refractive power, and a GRgroup including one or more lens groups, and changing focal length isperformed by varying intervals between the lens groups.

1-1-1. First Lens Group

The first lens group may have any detailed lens configuration if itgenerally has positive refractive power. For example, to achievefavorable aberration correction and provide a high-performance zoomlens, the first lens group preferably includes at least one negativelens. Further, the first lens group preferably includes, in order fromthe object side, a negative lens and a positive lens, more preferably,in order from the object side, a negative lens, a positive lens, and apositive lens. Consequently, while large positive refractive power isarranged in the first lens group, the amount of generation of sphericalaberration can be suppressed and a high zoom ratio can be attained. Itshould be noted that an appropriate lens configuration can be employeddepending on the required optical performance.

1-1-2. Second Lens Group

Similarly, the second lens group may have any detailed lensconfiguration if it generally has negative refractive power. Forexample, to achieve favorable aberration correction and provide ahigh-performance zoom lens, the second lens group preferably includes atleast one positive lens. It should be noted that an appropriate lensconfiguration can be employed depending on the required opticalperformance.

1-1-3. GR Group

The GR group, which includes one or more lens groups, is a general namefor the lens group arranged on the image side of the second lens groupin the zoom lens. The GR group includes one or more convex lens GpHsatisfying the following conditional expressions, and one or more convexlens GpL. The convex lens GpH and the convex lens GpL will be describedlater.

The GR group may consist of one lens group or a plurality of lensgroups. The larger the number of lens groups in the zoom lens, the moreadvantageous in achieving a high zoom ratio and high opticalperformance. On the other hand, the larger the number of lens groups inthe zoom lens, the more difficult the downsizing, weight reduction, andcost reduction of the zoom lens, and the more complicated the movingmechanism, etc. for moving the lens groups along the optical axis duringchanging focal length. In view of these points, the number of lensgroups in the GR group is preferably five or less, more preferably fouror less. In addition, the GR group preferably includes, in a positionclosest to the object, a third lens group having positive refractivepower, and more preferably, the GR group includes, in order from theobject side, the third lens group having positive refractive power and afourth lens group having positive refractive power.

In addition, the GR group may have either positive refractive power ornegative refractive power, but preferably has positive refractive poweras a whole. In the type of the zoom lens as in this example, at the wideangle end, the composite focal length of the first lens group and thesecond lens group is a negative value. For forming an object image onthe image plane, positive refractive power needs to be arranged in theGR group. For this reason, in the type of the zoom lens in this example,the entire GR group preferably has positive refractive power. Arrangingpositive refractive power in the GR group is also preferable forachieving a large-aperture zoom lens with a small F number as a whole.

In the zoom lens, the GR group preferably includes at least two cementedsurfaces having negative refractive power. In the case where the GRgroup consists of a plurality of lens groups, the cemented surfacehaving negative refractive power may be arranged in only one of the lensgroups or may be arranged in different lens groups.

In the present invention, a cemented surface having negative refractivepower refers to the following optical surface. First, a cemented surfacerefers to an interface between lenses cemented together in a cementedlens consisting of two or more lenses cemented together. A cementedsurface having negative refractive power means that the sign ofrefractive power (φ) of the cemented surface which is represented by thefollowing expression is negative (φ<0). It should be noted that, in thecase of a cemented surface which is a convergence surface, the sign ofrefractive power of the cemented surface is positive (φ>0).φ=(n2−n1)/rHere,φ is refractive power of the cemented surface,n1 is the refractive index of the lens arranged on the object side ofthe cemented surface,n2 is the refractive index of the lens arranged on the image plane sideof the cemented surface, andr is the curvature radius of the cemented surface (the sign of thecurvature radius of the cemented surface is positive if the center ofcurvature of the cemented surface is on the positive side than theintersection point of the cemented surface and the optical axis, and thesign of the curvature radius of the cemented surface is negative if thecenter of curvature of the cemented surface is on the negative side thanthe intersection point of the cemented surface and the optical axis,when the light traveling direction, i.e., the direction from the objectto the image plane is positive).

At least two cemented surfaces having negative refractive power in theGR group are arranged, so that negative spherical aberration andnegative longitudinal chromatic aberration that occur on a convergencesurface arranged in the GR group can be canceled out by the cementedsurfaces having negative refractive power. Consequently, highperformance zoom lens in which chromatic aberration in the entire zoomrange is well corrected is achieved.

To obtain the aforementioned advantageous effects, the GR grouppreferably includes at least one concave cemented surface on the objectside, and at least one concave cemented surface on the image plane side.The concave cemented surface on the object side is preferred forcorrection of mainly the spherical aberration and longitudinal chromaticaberration related to longitudinal ray. The concave cemented surface onthe image plane side is preferred for correction of mainly fieldcurvature and chromatic aberration of magnification.

Further, from view of these points of achieving preferred opticalperformance in a large-aperture zoom lens, the GR group preferablyincludes at least two concave cemented surfaces having negativerefractive power, on the object side. For example, the GR grouppreferably includes a cemented lens including a concave cemented surfaceon the object side and a concave cemented surface on the image planeside, i.e., a cemented lens consisting of three lenses cementedtogether, and a cemented lens including a concave cemented surfacehaving negative refractive power, on the object side (a cemented lensconsisting of two or more lenses cemented together).

(4) Aperture Stop

In the zoom lens, the aperture stop can be arranged in any position. Forexample, although an aperture stop is arranged on the object side in theGR group (i.e., on the image side of the second lens group) in theexample described below, in a zoom lens according to the presentinvention, an aperture stop may be arranged in any appropriate position,e.g., in the GR group or between the first lens group and the imageplane, depending on the size of the imaging device, the range of theimage viewing angle of the zoom lens, and the like. In this case, thefollowing conditional expression (3) is preferably satisfied.

(5) Operation During Changing Focal Length

In the zoom lens, changing focal length is performed by varyingintervals between the lens groups. In the present invention, varyingintervals between the lens groups during changing focal length meansthat the interval between the first lens group and the second lens groupand the interval between the second lens group and the GR group varyduring changing focal length. If the GR group consists of a plurality oflens groups, intervals between the lens groups in the GR group varyduring changing focal length. As long as the intervals between the lensgroups changes during changing focal length, all the lens groups may bemovable groups that move in the direction of the optical axis duringchanging focal length, or any one or more lens groups may be fixedgroups.

1-2. Conditional Expression

The zoom lens employs the aforementioned configuration and satisfies atleast one of the conditional expressions described below, therebyenabling favorable correction of chromatic aberration in the entire zoomrange. Hence, the zoom lens achieves higher performance and has asmaller size than conventional ones, and has high optical performance.

1-2-1. Conditional Expression (1)

The convex lens GpH included in the GR group satisfies the followingconditional expression (1).1.85<ndpH<2.50  (1)Here,ndpH is the refractive index related to the d-line of the convex lensGpH

The conditional expression (1) is an expression defining the refractiveindex related to the d-line of the convex lens GpH in the GR group.Since the convex lens satisfying the conditional expression (1) isarranged in the GR group, even if the aperture of the zoom lens isincreased, the occurrence of spherical aberration and coma aberrationcan be suppressed within an appropriate range, so that favorablecorrection of these aberrations can be achieved with a small number oflenses. Consequently, a compact zoom lens that exhibits high performancein the entire zoom range can be achieved at low cost.

In contrast, if the value of the conditional expression (1) is at orbelow the lower limit, the refractive index related to the d-line of theconvex lens GpH is lower than an appropriate value. Therefore, toprovide required refractive power to the convex lens GpH, the curvatureof each optical surface of the convex lens GpH should be large (thecurvature radius should be small). If the curvature of each opticalsurface is large, the spherical aberration and coma aberration occurringon the convex lens GpH are large. This makes it difficult to correctthese aberrations with a small number of lenses, to achieve aberrationcorrection in the entire optical system of the zoom lens, and to providea zoom lens that offers high performance and is compact in the entirezoom range.

In contrast, if the value of the conditional expression (1) is at orhigher the upper limit, the refractive index related to the d-line ofthe convex lens GpH is higher than the appropriate value. In this case,a reduction in optical performance due to surface figure irregularity(local distortion on an optical surface) and decentering is significant,and it is difficult to provide a zoom lens that offers high performanceand is compact in the entire zoom range due to the manufacturing error.

To obtain these advantageous effects, in the conditional expression (1),the lower limit is preferably 1.86, more preferably 1.90. The upperlimit in the expression is preferably 2.10, more preferably 2.00, morepreferably 1.94.

The convex lens GpH is arranged second position or after from objectside in positive lenses included in the Gr group, so that the convexlens GpH can be arranged in an optimum position for changeable height ofoff-axis ray during changing focal length. Consequently, fluctuations inthe secondary spectrum of longitudinal chromatic aberration can beminimized and favorable correction of chromatic aberration ofmagnification can be performed. Therefore, a high-performance zoom lensthat exhibits an extremely small chromatic aberration in the entire zoomrange can be achieved.

In contrast, if the convex lens GpH is arranged closest to the object inpositive lenses included in the GR group, compared with the case wherethe convex lens GpH is the positive lens in the second position orafter, a significant effect can be obtained in correction for thesecondary spectrum of longitudinal chromatic aberration, but the effectof correction for chromatic aberration of magnification is reduced. Thismakes it difficult to achieve favorable correction of chromaticaberration in the entire zoom range.

1-2-2. Conditional Expression (2)

The convex lens GpL included in the GR group satisfies the followingconditional expression (2).60.0<vdpL<100.0  (2)Here,vdpL is the Abbe constant related to the d-line of the convex lens GpL.

The conditional expression (2) defines the Abbe constant related to thed-line of the convex lens GpL in the GR group. When the conditionalexpression (2) is satisfied, at the telephoto end, positive longitudinalchromatic aberration caused by negative refractive power component inthe zoom lens can be corrected to negative. Consequently, the secondaryspectrum can be minimized, and the chromatic aberration related to thezoom lens can be made extremely small in the entire zoom range.

In contrast, if the value of the conditional expression (2) is at orbelow the lower limit, the Abbe constant related to the d-line of theconvex lens GpL is lower than an appropriate range, which means that,the convex lens GpL is composed of a high-dispersion glass materialcompared with the case where the conditional expression (2) issatisfied. In this case, positive longitudinal chromatic aberrationcaused by negative refractive power component in the zoom lens iscorrected excessively, which makes it difficult to make the chromaticaberration in the zoom lens small with a small number of lenses.

In contrast, if the value of the conditional expression (2) is at orabove the upper limit, the Abbe constant related to the d-line of theconvex lens GpL is higher than the appropriate range, which means that,the convex lens GpL is composed of a low-dispersion glass materialcompared with the case where the conditional expression (2) issatisfied. In this case, positive longitudinal chromatic aberrationcaused by negative refractive power component in the zoom lens iscorrected deficiently, which makes it difficult to make the chromaticaberration in the zoom lens small with a small number of lenses.

To obtain these advantageous effects, in the conditional expression (2),the lower limit is preferably 64.0, more preferably 68.0.

In the zoom lens, the GR group includes at least one convex lens GpLsatisfying the conditional expression (2). The GR group preferablyincludes multiple convex lenses GpL. The GR group preferably includestwo or more convex lenses GpL, more preferably three or more convexlenses GpL. When the GR group includes a plurality of convex lenses GpL,more favorable correction of the longitudinal chromatic aberration andthe chromatic aberration of magnification in the entire zoom range canbe achieved, so that it becomes easier to make the chromatic aberrationrelated to the zoom lens extremely small in the entire zoom range.

1-2-3. Conditional Expression (3)

The zoom lens preferably satisfies the following conditional expression(3).1.00<hGpH/hStop<2.00  (3)Here,hGpH is the maximum height from the optical axis when on-axis luminouspasses through the surface of the convex lens GpH on the object side, atthe telephoto end of the zoom lens, andhStop is the maximum height from the optical axis when on-axis luminouspasses through the aperture stop, at the telephoto end of the zoom lens.

The conditional expression (3) defines a ratio of the maximum heightfrom the optical axis when on-axis luminous flux passes through thesurface of the convex lens GpH on the object side to the maximum heightfrom the optical axis when on-axis luminous flux passes through theaperture stop, at the telephoto end of the zoom lens. When theconditional expression (3) is satisfied, the maximum height from theoptical axis when on-axis luminous flux passes through the surface ofthe convex lens GpH on the object side becomes within an appropriate,and positive longitudinal chromatic aberration caused by negativerefractive power component in the zoom lens can be corrected tonegative. Consequently, the secondary spectrum can be minimized, and thechromatic aberration related to the zoom lens can be made extremelysmall in the entire zoom range.

In contrast, if the value of the conditional expression (3) is at orbelow the lower limit, the maximum height from the optical axis whenon-axis luminous flux passes through the surface of the convex lens GpHon the object side falls below an appropriate range. In this case,positive longitudinal chromatic aberration caused by negative refractivepower component in the zoom lens is corrected deficiently, which makesit difficult to make the chromatic aberration in the zoom lens small.

In contrast, if the value of the conditional expression (3) is at orabove the upper limit, the maximum height from the optical axis whenon-axis luminous flux passes through the surface of the convex lens GpHon the object side exceeds the appropriate range. In this case, positivelongitudinal chromatic aberration caused by negative refractive powercomponent in the zoom lens is corrected excessively, which makes itdifficult to make the chromatic aberration in the zoom lens small.

To obtain these advantageous effects, in the conditional expression (3),the lower limit is preferably 1.10. The upper limit in the expression ispreferably 1.75, more preferably 1.50, more preferably 1.40.

1-2-4. Conditional Expression (4)

The convex lens GpH included in the GR group satisfies the followingconditional expression (4).10.0<vdpH<35.0  (4)Here,vdpH is the Abbe constant related to the d-line of the convex lens GpH.

The conditional expression (4) defines the Abbe constant related to thed-line of the convex lens GpH in the GR group. When the conditionalexpression (4) is satisfied, at the telephoto end, positive longitudinalchromatic aberration caused by negative refractive power component inthe zoom lens can be corrected to negative. Consequently, the secondaryspectrum can be minimized, and the chromatic aberration related to thezoom lens can be made extremely small in the entire zoom range.

In contrast, if the value of the conditional expression (4) is at orbelow the lower limit, the Abbe constant related to the d-line of theconvex lens GpH is lower than an appropriate range, which means that,the convex lens GpH is composed of a high-dispersion glass materialcompared with the case where the conditional expression (4) issatisfied. In this case, positive longitudinal chromatic aberrationcaused by negative refractive power component in the zoom lens iscorrected excessively, which makes it difficult to make the chromaticaberration in the zoom lens small.

In contrast, if the value of the conditional expression (4) is at orabove the upper limit, the Abbe constant related to the d-line of theconvex lens GpH is higher than the appropriate range, which means that,the convex lens GpH is composed of a low-dispersion glass materialcompared with the case where the conditional expression (4) issatisfied. In this case, positive longitudinal chromatic aberrationcaused by negative refractive power component in the zoom lens iscorrected deficiently, which makes it difficult to make the chromaticaberration in the zoom lens small.

To obtain these advantageous effects, in the conditional expression (4),the lower limit is preferably 15.0, more preferably 17.5. The upperlimit in the expression is preferably 33.00, more preferably 30.0, morepreferably 25.0.

In the zoom lens, the GR group includes at least one convex lens GpHsatisfying the conditional expressions (1) and (2). In terms ofaberration correction, although the GR group can include a plurality ofconvex lenses GpH as necessary, a single convex lens GpH is enough toachieve reductions in the size and cost of the zoom lens.

Here, it is preferable that the GR group include at least one lens grouphaving positive refractive power, and the convex lens GpH be arranged ina lens group having positive refractive power in the GR group. Theconvex lens GpH in the GR group is arranged in the lens group havingpositive refractive power, thereby suppressing a negative sphericalaberration that occurs at the telephoto end. At the same time, positivelongitudinal chromatic aberration that occurs at the telephoto end canbe corrected to negative, and the secondary spectrum can be minimized,thereby facilitating the completion of a zoom lens with extremely smallchromatic aberration in the entire zoom range.

More preferably, the convex lens GpH is a single lens having positiverefractive power. A single lens refers to a single lens (opticalelement) including optical surfaces arranged on the object side and theimage plane side, respectively. In the single lens, various coatings,such as an anti-reflecting film and a protection film, may be applied tothese optical surfaces or an aspherical sheet or the like may be appliedto the optical surfaces. An optical surface in the single lens may haveany shape, for example, a spherical or aspherical shape. The opticalsurface may be flat on one side. The single lens may be manufactured byany method, such as polishing, molding, or injection molding. A singlelens here is a lens consisting of only one single lens, and is excepted,for example, a plurality of lenses including a positive lens and anegative lens the optical surfaces of which are cemented or in closecontact without an air layer therebetween.

1-2-5. Conditional Expression (5)

The zoom lens preferably satisfies the following conditional expression(5).0.90<f1/fw<15.00  (5)Here,f1 is the focal length of the first lens group, andfw is the focal length of the zoom lens at the wide angle end.

The conditional expression (5) defines a ratio of the focal length ofthe first lens group to the focal length of the zoom lens at the wideangle end. Since the conditional expression (5) is satisfied, theoccurrence of spherical aberration and coma aberration occurring in thefirst lens group can be suppressed within an appropriate range, so thatfavorable aberration correction can be achieved with a small number oflenses. At the same time, the amount of movement of the first lens groupfor obtaining a predetermined magnification can fall within anappropriate range. Consequently, the zoom lens can offer highperformance and be made compact in the entire zoom range.

In contrast, if the value of the conditional expression (5) is at orbelow the lower limit, the ratio of the focal length of the first lensgroup to the focal length of the zoom lens at the wide angle end fallsbelow an appropriate range. In other words, refractive power of thefirst lens group becomes strong, exceeding an appropriate range. In thiscase, at the wide angle end, the occurrence of spherical aberration andcoma aberration in the first lens group exceeds an appropriate range,which makes it difficult to obtain favorable optical performance in theentire zoom range.

In contrast, if the value of the conditional expression (5) is at orabove the upper limit, the ratio of the focal length of the first lensgroup to the focal length of the zoom lens at the wide angle end exceedsthe appropriate range. In other words, refractive power of the firstlens group becomes weak, falling below the appropriate range. In thiscase, the amount of movement of the first lens group for obtaining apredetermined magnification becomes large, exceeding the appropriaterange. Consequently, the full length of the zoom lens increases, whichmakes it difficult to reduce the size of the zoom lens relative to theoverall product. In a typical zoom lens, one or more inner tubes arenestled within a lens barrel (outermost tube). If the difference betweenthe entire optical lengths at the telephoto end and the wide angle endincreases, in order to shorten the full length of the lens barrel withthe inner tubes accommodated within the lens barrel, the plurality ofinner tubes is accommodated in the outermost tube. This is notpreferable because, in this case, a cam structure for ejecting the lensbarrel (the inner tubes) is complicated, the diameter of the outermosttube is made large considering the thickness of the inner tubes, and thebarrel has a large outer diameter.

To obtain these advantageous effects, in the conditional expression (5),the lower limit is preferably 1.50, more preferably 2.00, morepreferably 2.50, more preferably 3.00, more preferably 3.15, morepreferably 3.30. The upper limit is preferably 6.75, more preferably5.50, more preferably 5.30, more preferably 5.10.

1-2-6. Conditional Expression (6)

The zoom lens preferably satisfies the following conditional expression(6).0.95<Fno_ t<5.60  (6)Here,Fno_t is the F number of the zoom lens at the telephoto end.

The conditional expression (6) defines the F number of the zoom lens atthe telephoto end. If the conditional expression (6) is satisfied, moreeffective correction of the longitudinal chromatic aberration at thetelephoto end can be achieved, favorable correction of the longitudinalchromatic aberration and chromatic aberration of magnification in theentire zoom range can be achieved, and the zoom lens can exhibit higheroptical performance.

To obtain these advantageous effects, in the conditional expression (6),the lower limit is preferably 1.20, more preferably 1.40, morepreferably 1.80, and more preferably 2.00. The upper limit is preferably4.50.

2. Imaging Apparatus

An imaging apparatus of the present invention will now be described. Animaging apparatus according to the present invention includes the zoomlens according to the present invention and an imaging device that isarranged on the image side of the zoom lens and converts an opticalimage formed by the zoom lens to electrical signals. Here, any imagingdevice, for example, a solid-state imaging device, such as a CCD sensoror a CMOS sensor, can be used. An imaging apparatus of the presentinvention is suitable for a digital camera or a video camera and animaging apparatus including any of these imaging devices. Notsurprisingly, the imaging apparatus may be a lens-fixed imagingapparatus in which a lens is fixed to a housing, or an interchangeablelens imaging apparatus, such as an SLR or mirrorless interchangeablelens camera.

The details of the present invention will now be described withreference to an example. It should be noted that the present inventionis not limited to the following example. The optical system in each ofthe following examples is a shooting optical system used for a digitalcamera, a video camera, or an imaging apparatus (optical device), suchas a silver-salt film camera. In addition, in the cross sectional viewof each lens, the left side corresponds to the object side and the rightside corresponds to the image side.

Example 1

(1) Configuration of Optical System

FIG. 1 is a cross-sectional view of a lens configuration example of azoom lens of Example 1 of the present invention. The zoom lens consistsof, in order from the object side, a first lens group G1 having positiverefractive power, a second lens group G2 having negative refractivepower, a third lens group G3 having positive refractive power, and afourth lens group having positive refractive power, and changing focallength is performed by varying intervals between the lens groups. Duringchanging focal length from the wide angle end to the telephoto end, thefirst lens group G1 moves toward the object, the second lens group G2moves toward the object in such a manner that it draws a path protrudingtoward the image plane, the third lens group G3 moves toward the object,and the fourth lens group G4 moves toward the object. The moving pathsof the lens groups are all different.

In the zoom lens of Example 1, the third lens group G3 and the fourthlens group G4 constitute a GR group of the present invention. The 17thsurface and the 18th surface included in the third lens group G3, andthe 25th surface and the 28th surface included in the fourth lens groupG4 are cemented surfaces having negative refractive power in the presentinvention (see Table 1). In addition, in the third lens group G3, thelens closest to the image plane and having the 20th surface and the 21stsurface is a convex lens GpH in the present invention (see Table 1).Further, the lens, included in the third lens group, that has the 17thsurface and the 18th surface and constitutes a cemented lens; the lens,included in the fourth lens group G4, that is closest to the object inthe group and has the 22nd surface and the 23rd surface; the lens thathas the 24th surface and the 25th surface and constitutes a cementedlens; and the lens that has the 28th surface and the 29th surface andconstitutes a cemented lens are convex lenses GpL in the presentinvention (see Table 1).

In the drawings, “S” represents an aperture stop, and “I” represents animage plane, specifically, the imaging surface of a solid-state imagingdevice, such as a CCD sensor or a CMOS sensor, or the film surface of asilver-salt film, for example. The detailed lens configuration of eachlens group is as shown in FIG. 1. It should be noted that thedescription of these reference numerals, which represent the samecomponents in the drawings related to Examples 2 to 9, will be omittedbelow.

(2) Typical Numerical Values

Explanation will now be given of Typical numerical value 1 of the zoomlens to which specific numerical values are applied. Table 1 shows lensdata related to the zoom lens. In Table 1, “No.” shows the order of alens surface from the object side, “R” shows the curvature radius of thelens surface, “D” shows the distance between lens surfaces on theoptical axis, “Nd” shows a refractive index related to a d-line(wavelength λ=587.56 nm), and “νd” shows an Abbe constant related to thed-line (wavelength λ=587.60 nm). In addition, an aperture stop (apertureS) is denoted by a surface number followed by “STOP”. Further, a lenssurface, which is aspherical, is denoted by a surface number followed by“ASPH”, and is expressed with a paraxial curvature radius in the fieldof curvature radius R.

For an aspherical surface, the aspherical factor and the conic constantused to represent its shape in the following expression are shown inTable 2. An aspherical surface is defined by the following expression.z=ch ²/[1+{1−(1+k)c ² h ²}^(1/2)]+A4h ⁴ +A6h ⁶ +A8h ⁸ +A10h ¹⁰ +A12h ¹²+A14h ¹⁴ +A16h ¹⁶ +A18h ¹⁸ +A20h ²⁰

Here, c is a curvature (1/r), h is the height from the optical axis, kis the conic constant, and A4, A6, A8, A10, A12, A14, A16, A18, and A20are the aspherical factors of the respective orders.

Table 3 shows the F number (Fno) of the zoom lens having each focallength (F), half image viewing angle (W), and the lens interval betweenmovable group which moves during changing focal length and the adjacentlens group on its image side.

It should be noted that the matters related these tables are the same inthe tables shown in Examples 2 to 9, and their description willtherefore be omitted below.

FIGS. 2 to 4 shows longitudinal aberrations diagrams of the zoom lens ata time of focusing to infinity at the wide angle end, the middle focallength, and the telephoto end, respectively. Each diagram of alongitudinal aberration shows, from the left, spherical aberration,astigmatism, and distortion aberration. In each diagram of sphericalaberration, the vertical axis represents a proportion to a maximumaperture, the horizontal axis represents defocus, and the solid linerepresents a d-line (587.56 nm), and the dashed line represents a g-line(435.84 nm). In each diagram of an astigmatism, the vertical axisrepresents an image viewing angle, the horizontal axis representsdefocus, and the solid line represents the sagittal direction (S) of ad-line, and the dashed line represents the meridional direction (T) ofthe d-line. In each diagram of distortion aberration, the vertical axisrepresents an image viewing angle, and the horizontal axis represents apercentage. It should be noted that the order of presentation ofaberrations and what the solid line, the dotted line, and the likerepresent in each diagram are the same in the diagrams shown in Examples2 to 9, and their description will therefore be omitted below.

The focal lengths (f1, f2, f3, and f4) of the respective lens groups areshown in Table 28. Table 28 also shows the value of the conditionalexpression (3) “hGpH/hStop”, and the value of the conditional expression(5) “f1/fw”. See Table 1 for values related to the conditionalexpressions (1), (2) and (4), and see Table 3 for values related to theconditional expression (6).

TABLE 1 No. R D Nd νd  1 206.25950 0.80000 1.92286 20.88  2 105.476404.62240 1.61800 63.39  3 552.16740 0.20000  4 52.61360 5.73810 1.6968055.46  5 123.90690 D(5)   6 ASPH 115.83650 0.30000 1.51460 49.96  772.77880 1.00000 1.72916 54.67  8 16.84340 6.54830  9 −45.90970 0.800001.60562 43.71 10 21.65710 5.56360 1.76182 26.61 11 −92.36210 5.83950 12−17.86200 0.80000 1.69680 55.46 13 −28.02270 0.20000 1.51460 49.96 14ASPH −28.02270 D(14) 15 STOP ∞ 1.00000 16 53.23810 0.80000 1.92286 20.8817 35.22620 10.79820  1.49700 81.61 18 −19.68920 0.80000 1.80420 46.5019 −50.65210 0.69150 20 198.35320 2.66540 1.92286 20.88 21 −165.94390D(21) 22 40.15550 8.40400 1.59349 67.00 23 −55.92290 0.20000 24−112.46930 5.17930 1.49700 81.61 25 −31.92030 0.80000 1.90366 31.31 26−62.31770 0.20000 27 30.82620 2.17370 1.80420 46.50 28 16.56920 5.869801.49700 81.61 29 35.13670 5.09950 30 ASPH −216.67320 0.20000 1.5146049.96 31 −99.71870 1.00000 1.48749 70.44 32 −2145.44910 D(32) 33 ∞2.00000 1.51680 64.20 34 ∞ 1.00000

TABLE 2 No. K A4 A6 A8 A10  6 0.00000E+00 1.14541E−05 −5.91316E−094.63776E−11 −1.69037E−13 14 0.00000E+00 −4.10185E−06  −1.71684E−083.67008E−11 −1.96302E−13 30 0.00000E+00 −1.94448E−05  −1.78252E−08−3.07457E−12  −2.25995E−13 No. A12 A14 A16 A18 A20  6 5.02394E−160.00000E+00  0.00000E+00 0.00000E+00  0.00000E+00 14 0.00000E+000.00000E+00  0.00000E+00 0.00000E+00  0.00000E+00 30 0.00000E+000.00000E+00  0.00000E+00 0.00000E+00  0.00000E+00

TABLE 3 F 28.8580 43.6467 72.7337 Fno 2.9232 2.9123 2.9230 W 37.865826.2400 16.2477 D(5) 3.4612 15.4239 32.0740 D(14) 12.8313 6.2213 0.5029D(21) 6.6361 2.6888 0.5000 D(32) 35.7783 45.4571 57.6298

Example 2

(1) Configuration of Optical System

FIG. 5 is a cross-sectional view of a lens configuration example of azoom lens of Example 2 of the present invention. The zoom lens consistsof, in order from the object side, a first lens group G1 having positiverefractive power, a second lens group G2 having negative refractivepower, a third lens group G3 having positive refractive power, and afourth lens group having positive refractive power, and changing focallength is performed by varying intervals between the lens groups. Duringchanging focal length from the wide angle end to the telephoto end, thefirst lens group G1 moves toward the object, the second lens group G2moves toward the object in such a manner that it draws a path protrudingtoward the image plane, the third lens group G3 moves toward the object,and the fourth lens group G4 moves toward the object. The moving pathsof the lens groups are all different.

In the zoom lens of Example 2, the third lens group G3 and the fourthlens group G4 constitute a GR group of the present invention. The 17thsurface and the 18th surface included in the third lens group G3, andthe 23rd surface and the 26th surface included in the fourth lens groupG4 are cemented surfaces having negative refractive power in the presentinvention (see Table 4). In addition, in the third lens group G3, thelens closest to the image plane and having the 20th surface and the 21stsurface is a convex lens GpH in the present invention (see Table 4).Further, the lens, included in the third lens group, that has the 17thsurface and the 18th surface and constitutes a cemented lens; the lens,included in the fourth lens group G4, that is closest to the object inthe group, constitutes a cemented lens, and has the 22nd surface and the23rd surface; and the following lens that constitutes a cemented lensand has the 26th surface and the 27th surface are convex lenses GpL inthe present invention (see Table 4).

(2) Typical Numerical Values

Explanation will now be given of Typical numerical value 2 of the zoomlens to which specific numerical values are applied. Table 4 shows lensdata related to the zoom lens. For an aspherical surface, the asphericalfactor and the conic constant are shown in Table 5. Table 6 shows the Fnumber (Fno) of the zoom lens having each focal length (F), the halfimage viewing angle (W), and the lens interval between movable groupwhich moves during changing focal length and the adjacent lens group onits image side. FIGS. 5 to 8 are longitudinal aberrations diagrams ofthe zoom lens at a time of focusing to infinity. Table 28 shows thefocal lengths (f1, f2, f3, and f4) of the respective lens groups and thevalues in the conditional expressions (3) and (5). See Table 4 forvalues related to the conditional expressions (1), (2) and (4), and seeTable 6 for values related to the conditional expression (6).

TABLE 4 No. R D Nd νd  1 273.7418 0.8000 1.92286 20.88  2 127.67784.3414 1.61800 63.39  3 1159.8271 0.2000  4 54.6742 5.3540 1.69680 55.46 5 120.5502 D(5)   6ASPH 92.7077 0.3000 1.51460 49.96  7 68.4825 1.00001.72916 54.67  8 17.2217 6.5362  9 −52.3680 0.8000 1.60562 43.71 1020.8717 5.5815 1.76182 26.61 11 −123.0575 6.4748 12 −18.2473 0.80001.69680 55.46 13 −29.4806 0.2000 1.51460 49.96 14ASPH −29.4806 D(14)15STOP ∞ 1.0000 16 58.9832 1.0000 1.92286 20.88 17 36.2082 10.3244 1.49700 81.61 18 −20.6322 0.8000 1.80420 46.50 19 −41.7816 0.2000 20110.8326 2.3985 1.92286 20.88 21 −1243.0628 D(21) 22 34.0190 10.6864 1.59282 68.62 23 −37.3010 0.8000 1.90366 31.31 24 −63.6616 1.5540 2531.0017 0.8753 1.80420 46.50 26 15.9071 6.1139 1.49700 81.61 27 33.47455.6357 28ASPH −122.8934 0.2000 1.51460 49.96 29 −72.3046 1.0000 1.4874970.44 30 −206.0011 D(30) 31 ∞ 2.0000 1.51680 64.20 32 ∞ 1.0000

TABLE 5 No. K A4 A6 A8 A10  6 0.00000E+00 9.21610E−06 −1.61619E−102.55874E−11 −9.47994E−14 14 0.00000E+00 −3.65150E−06  −1.82836E−087.95403E−11 −3.10116E−13 28 0.00000E+00 −1.91716E−05  −3.37346E−089.83411E−11 −6.77413E−13 No. A12 A14 A16 A18 A20  6 3.34149E−160.00000E+00  0.00000E+00 0.00000E+00  0.00000E+00 14 0.00000E+000.00000E+00  0.00000E+00 0.00000E+00  0.00000E+00 28 0.00000E+000.00000E+00  0.00000E+00 0.00000E+00  0.00000E+00

TABLE 6 F 28.8615 43.6453 72.7476 Fno 2.9003 2.916 2.912 W 37.815126.2524 16.2527 D(5)  3.4266 13.8084 34.878 D(14) 12.9613 5.7232 0.5004D(21) 8.3455 3.4872 1.1191 D(30) 35.3233 46.5242 57.5264

Example 3

(1) Configuration of Optical System

FIG. 9 is a cross-sectional view of a lens configuration example of azoom lens of Example 3 of the present invention. The zoom lens consistsof, in order from the object side, a first lens group G1 having positiverefractive power, a second lens group G2 having negative refractivepower, a third lens group G3 having positive refractive power, and afourth lens group having positive refractive power, and changing focallength is performed by varying intervals between the lens groups. Duringchanging focal length from the wide angle end to the telephoto end, thefirst lens group G1 to the fourth lens group G4 follow different pathsto move toward the object.

In the zoom lens of Example 3, the third lens group G3 and the fourthlens group G4 constitute a GR group of the present invention. The 17thsurface and the 18th surface included in the third lens group G3, andthe 23rd surface and the 26th surface included in the fourth lens groupG4 are cemented surfaces having negative refractive power in the presentinvention (see Table 7). In addition, in the third lens group G3, thelens closest to the image plane and having the 20th surface and the 21stsurface is a convex lens GpH in the present invention (see Table 7).Further, the lens, included in the third lens group, that has the 17thsurface and the 18th surface and constitutes a cemented lens; the lens,included in the fourth lens group G4, that is closest to the object inthe group, constitutes a cemented lens, and has the 22nd surface and the23rd surface; and the following lens that constitutes a cemented lensand has the 26th surface and the 27th surface are convex lenses GpL inthe present invention (see Table 7).

(2) Typical Numerical Values

Explanation will now be given of Typical numerical value 3 of the zoomlens to which specific numerical values are applied. Table 7 shows lensdata related to the zoom lens. For an aspherical surface, the asphericalfactor and the conic constant are shown in Table 8. Table 9 shows the Fnumber (Fno) of the zoom lens having each focal length (F), the halfimage viewing angle (W), and the lens distance of each lens group(movable group) from the adjacent lens group on its image side movingduring changing focal length. FIGS. 10 to 12 are diagrams showinglongitudinal aberrations occurring while the zoom lens are in infinitefocus. Table 28 shows the focal lengths (f1, f2, f3, and f4) of therespective lens groups and the values in the conditional expressions (3)and (5). See Table 7 for values related to the conditional expressions(1), (2) and (4), and see Table 9 for values related to the conditionalexpression (6).

TABLE 7 No. R D Nd νd  1 63.8944 0.8000 1.92286 20.88  2 53.2990 5.68251.49700 81.61  3 110.1485 0.2000  4 60.6681 5.3003 1.59282 68.62  5161.1727 D(5)   6ASPH 141.3391 0.3000 1.51460 49.96  7 92.6708 1.00001.72916 54.67  8 16.7772 6.4186  9 −54.3686 0.8000 1.56883 56.36 1016.8054 9.0993 1.64769 33.84 11 −47.8220 2.0378 12 −19.1205 0.80001.72916 54.67 13 −35.5757 0.2000 1.51460 49.96 14ASPH −35.5757 D(14)15STOP ∞ 1.0000 16 52.8451 0.5000 1.92286 20.88 17 36.9595 7.39931.49700 81.61 18 −19.0480 0.8000 1.80420 46.5 19 −56.1874 0.2000 20218.0432 1.8427 1.92286 20.88 21 −144.3735 D(21) 22 35.4970 9.32471.59282 68.62 23 −28.6508 0.8000 2.00100 29.13 24 −43.0595 0.2712 2530.6853 2.6206 1.77250 49.62 26 14.7798 5.9929 1.49700 81.61 27 27.60854.2215 28ASPH −83.8550 0.2000 1.51460 49.96 29 −63.8146 1.0000 1.4874970.44 30 −117.1399 D(30) 31 ∞ 2.0000 1.51680 64.2 32 ∞ 1.0000

TABLE 8 No. K A4 A6 A8 A10  6 0.00000E+00 1.18407E−05 −1.63549E−081.63556E−10 −6.83717E−13 14 0.00000E+00 −6.38264E−06  −1.92562E−081.14299E−10 −3.95171E−13 28 0.00000E+00 −2.15995E−05  −4.67680E−081.32958E−10 −1.32141E−12 No. A12 A14 A16 A18 A20  6 1.38615E−150.00000E+00  0.00000E+00 0.00000E+00  0.00000E+00 14 0.00000E+000.00000E+00  0.00000E+00 0.00000E+00  0.00000E+00 28 0.00000E+000.00000E+00  0.00000E+00 0.00000E+00  0.00000E+00

TABLE 9 F 28.8722 51.3877 101.8262 Fno 4.1094 4.0957 4.1517 W 37.667022.5987 11.7613 D(5)  3.7447 17.1253 39.5947 D(14) 17.7933 7.6993 0.5028D(21) 6.8854 2.3225 0.5000 D(30) 37.9586 53.3945 70.5912

Example 4

(1) Configuration of Optical System

FIG. 13 is a cross-sectional view of a lens configuration example of azoom lens of Example 4 of the present invention. The zoom lens consistsof, in order from the object side, a first lens group G1 having positiverefractive power, a second lens group G2 having negative refractivepower, a third lens group G3 having positive refractive power, and afourth lens group having positive refractive power, and changing focallength is performed by varying intervals between the lens groups. Duringchanging focal length from the wide angle end to the telephoto end, thefirst lens group G1 to the fourth lens group G4 follow different pathsto move toward the object.

In the zoom lens of Example 4, the third lens group G3 and the fourthlens group G4 constitute a GR group of the present invention. The 17thsurface and the 18th surface included in the third lens group G3, andthe 23rd surface and the 26th surface included in the fourth lens groupG4 are cemented surfaces having negative refractive power in the presentinvention (see Table 10). In addition, in the third lens group G3, thelens closest to the image plane and having the 20th surface and the 21stsurface is a convex lens GpH in the present invention (see Table 10).Further, the lens, included in the third lens group, that has the 17thsurface and the 18th surface and constitutes a cemented lens; the lens,included in the fourth lens group G4, that is closest to the object inthe group, constitutes a cemented lens, and has the 22nd surface and the23rd surface; and the following lens that constitutes a cemented lensand has the 26th surface and the 27th surface are convex lenses GpL inthe present invention (see Table 10).

(2) Typical Numerical Values

Explanation will now be given of Typical numerical value 4 of the zoomlens to which specific numerical values are applied. Table 10 shows lensdata related to the zoom lens. For an aspherical surface, the asphericalfactor and the conic constant are shown in Table 11. Table 12 shows theF number (Fno) of the zoom lens having each focal length (F), the halfimage viewing angle (W), and the lens interval between movable groupwhich moves during changing focal length and the adjacent lens group onits image side. FIGS. 14 to 16 are longitudinal aberrations diagrams ofthe zoom lens at a time of focusing to infinity. Table 28 shows thefocal lengths (f1, f2, f3, and f4) of the respective lens groups and thevalues in the conditional expressions (3) and (5). See Table 10 forvalues related to the conditional expressions (1), (2) and (4), and seeTable 12 for values related to the conditional expression (6).

TABLE 10 No. R D Nd νd  1 61.5786 0.8000 1.92286 20.88  2 52.0510 5.73991.49700 81.61  3 106.4012 0.2000  4 63.0821 4.9356 1.59282 68.62  5153.2269 D(5)   6ASPH 155.9684 0.3000 1.51460 49.96  7 83.7613 1.00001.72916 54.67  8 17.1990 6.6068  9 −61.2404 0.8000 1.56883 56.36 1017.1285 9.0362 1.64769 33.84 11 −49.9502 2.2606 12 −19.4312 0.80001.72916 54.67 13 −36.8713 0.2000 1.51460 49.96 14ASPH −36.8713 D(14)15STOP ∞ 1.0000 16 65.5383 0.5000 1.94595 17.98 17 39.3437 7.44921.59349 67.00 18 −18.5719 0.8000 1.80420 46.50 19 −74.4273 0.2000 20126.2989 1.8161 1.94595 17.98 21 −303.2145 D(21) 22 32.3007 9.39981.59282 68.62 23 −30.0473 0.8000 2.00100 29.13 24 −46.6951 0.6219 2530.0832 1.5814 1.77250 49.62 26 14.2447 6.1504 1.49700 81.61 27 27.11314.2811 28ASPH −75.1949 0.2000 1.51460 49.96 29 −59.0799 1.0000 1.4874970.44 30 −108.1864 D(30) 31 ∞ 2.0000 1.51680 64.20 32 ∞ 1.0000

TABLE 11 No. K A4 A6 A8 A10  6 0.00000E+00 1.14500E−05 −1.48891E−081.33519E−10 −5.07198E−13 14 0.00000E+00 −6.02882E−06  −2.28893E−081.67325E−10 −6.47292E−13 28 0.00000E+00 −2.18758E−05  −5.11023E−081.62336E−10 −1.56674E−12 No. A12 A14 A16 A18 A20  6 9.51179E−160.00000E+00  0.00000E+00 0.00000E+00  0.00000E+00 14 0.00000E+000.00000E+00  0.00000E+00 0.00000E+00  0.00000E+00 28 0.00000E+000.00000E+00  0.00000E+00 0.00000E+00  0.00000E+00

TABLE 12 F 28.8734 51.3899 101.8139 Fno 4.0979 4.0767 4.1371 W 37.523422.5913 11.7634 D(5)  3.8463 16.9640 40.6476 D(14) 18.2661 7.7430 0.5043D(21) 7.2468 2.3605 0.5000 D(30) 36.8313 52.5564 69.8694

Example 5

(1) Configuration of Optical System

FIG. 17 is a cross-sectional view of a lens configuration example of azoom lens of Example 5 of the present invention. The zoom lens consistsof, in order from the object side, a first lens group G1 having positiverefractive power, a second lens group G2 having negative refractivepower, a third lens group G3 having positive refractive power, and afourth lens group having positive refractive power, and changing focallength is performed by varying intervals between the lens groups. Duringchanging focal length from the wide angle end to the telephoto end, thefirst lens group G1 moves toward the object, the second lens group movestoward the object in such a manner that it draws a path protrudingtoward the image plane, the third lens group G3 moves toward the object,and the fourth lens group G4 moves toward the object. The moving pathsof the lens groups are all different.

In the zoom lens of Example 5, the third lens group G3 and the fourthlens group G4 constitute a GR group of the present invention. The 17thsurface and the 18th surface included in the third lens group G3, andthe 25th surface and the 28th surface included in the fourth lens groupG4 are cemented surfaces having negative refractive power in the presentinvention (see Table 13). In addition, in the third lens group G3, thelens closest to the image plane and having the 20th surface and the 21stsurface is a convex lens GpH in the present invention (see Table 13).Further, the lens, included in the third lens group, that has the 17thface and the 18th face and constitutes a cemented lens; the lens,included in the fourth lens group G4, that is closest to the object inthe group and has the 22nd face and the 23rd face; the following lensthat has the 24th face and the 25th face and constitutes a cementedlens; and the lens following farther that has the 28th face and the 29thface and constitutes a cemented lens are convex lenses GpL in thepresent invention (see Table 13).

(2) Typical Numerical Values

Explanation will now be given of Typical numerical value 5 of the zoomlens to which specific numerical values are applied. Table 13 shows lensdata related to the zoom lens. For an aspherical surface, the asphericalfactor and the conic constant are shown in Table 14. Table 15 shows theF number (Fno) of the zoom lens having each focal length (F), the halfimage viewing angle (W), and the lens interval between movable groupwhich moves during changing focal length and the adjacent lens group onits image side. FIGS. 18 to 20 are longitudinal aberrations diagrams ofthe zoom lens at a time of focusing to infinity. Table 28 shows thefocal lengths (f1, f2, f3, and f4) of the respective lens groups and thevalues in the conditional expressions (3) and (5). See Table 13 forvalues related to the conditional expressions (1), (2) and (4), and seeTable 15 for values related to the conditional expression (6).

TABLE 13 No. R D Nd νd  1 135.7175 0.8000 1.92286 20.88  2 84.59175.0219 1.61997 63.88  3 203.8066 0.2000  4 57.9825 6.8816 1.69680 55.46 5 167.4220 D(5)   6ASPH 121.5119 0.3000 1.51460 49.96  7 73.8870 1.00001.72916 54.67  8 16.5921 8.2341  9 −49.4155 0.9792 1.83481 42.72 1021.8307 6.5169 2.00100 29.13 11 −89.8329 3.8827 12 −20.4352 0.80001.72916 54.67 13 −35.2270 0.2000 1.51460 49.96 14ASPH −35.2270 D(14)15STOP ∞ 1.0000 16 53.0947 0.8000 1.92286 20.88 17 30.7289 10.1458 1.49700 81.61 18 −19.1143 0.8000 1.77250 49.62 19 −95.5054 0.2000 20192.2312 3.4715 1.92286 20.88 21 −82.3958 D(21) 22 36.6584 7.47971.61997 63.88 23 −81.9954 1.9809 24 −191.2280 4.7303 1.49700 81.61 25−35.9632 0.8000 1.92119 23.96 26 −69.0006 0.2000 27 30.1487 0.80001.83481 42.72 28 16.5401 6.0585 1.49700 81.61 29 39.5339 5.1704 30ASPH−153.1941 0.2000 1.51460 49.96 31 −84.6842 1.0000 1.48749 70.44 32−120.4974 D(32) 33 ∞ 2.0000 1.51680 64.20 34 ∞ 1.0000

TABLE 14 No. K A4 A6 A8 A10  6 0.00000E+00   1.17659E−05 −1.71813E−089.92318E−11 −3.11252E−13 14 0.00000E+00 −1.47671E−06 −1.57141E−088.36707E−11 −3.05218E−13 30 0.00000E+00 −1.83853E−05 −2.66019E−087.48453E−11 −4.73022E−13 No. A12 A14 A16 A18 A20  6 5.02644E−160.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 14 0.00000E+000.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 30 0.00000E+000.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00

TABLE 15 F 24.7626 42.2135 67.8916 Fno 2.9207 2.9127 2.9224 W 42.326826.9311 17.2675 D(5) 2.7009 14.7764 32.2706 D(14) 14.4813 5.1983 0.5017D(21) 8.0970 2.5443 0.5000 D(32) 35.0000 48.7335 59.0745

Example 6

(1) Configuration of Optical System

FIG. 21 is a cross-sectional view of a lens configuration example of azoom lens of Example 6 of the present invention. The zoom lens consistsof, in order from the object side, a first lens group G1 having positiverefractive power, a second lens group G2 having negative refractivepower, a third lens group G3 having positive refractive power, and afourth lens group G4 having positive refractive power, and a fifth lensgroup G5 having negative refractive power, and changing focal length isperformed by varying intervals between the lens groups. During changingfocal length from the wide angle end to the telephoto end, the firstlens group G1 to the fifth lens group G5 follow different paths to movetoward the object.

In the zoom lens of Example 6, the third lens group G3 to the fifth lensgroup G5 constitute a GR group of the present invention. The 17thsurface and the 18th surface included in the third lens group G3, andthe 23rd surface and the 26th surface included in the fourth lens groupG4 are cemented surfaces having negative refractive power in the presentinvention (see Table 16). In addition, in the third lens group G3, thelens closest to the image plane and having the 20th surface and the 21stsurface is a convex lens GpH in the present invention (see Table 16).Further, the lens, included in the third lens group, that has the 17thsurface and the 18th surface and constitutes a cemented lens; the lens,included in the fourth lens group G4, that is closest to the object inthe group, constitutes a cemented lens, and has the 22nd surface and the23rd surface; and the lens that is closest to the object in the fifthlens group and has the 31st surface and the 32nd surface are convexlenses GpL in the present invention (see Table 16).

(2) Typical Numerical Values

Explanation will now be given of Typical numerical value 6 of the zoomlens to which specific numerical values are applied. Table 16 shows lensdata related to the zoom lens. For an aspherical surface, the asphericalfactor and the conic constant are shown in Table 17. Table 18 shows theF number (Fno) of the zoom lens having each focal length (F), the halfimage viewing angle (W), and the lens interval between movable groupwhich moves during changing focal length and the adjacent lens group onits image side. FIGS. 22 to 24 are longitudinal aberrations diagrams ofthe zoom lens at a time of focusing to infinity. Table 28 shows thefocal lengths (f1, f2, f3, f4, and f5) of the respective lens groups andthe values in the conditional expressions (3) and (5). See Table 16 forvalues related to the conditional expressions (1), (2) and (4), and seeTable 18 for values related to the conditional expression (6).

TABLE 16 No. R D Nd νd  1 207.5498 0.8000 1.84666 23.78  2 103.26135.4524 1.49700 81.61  3 −2007.5310 0.2000  4 53.0038 6.3307 1.5928268.62  5 196.7987 D(5)   6ASPH 70.4062 0.3000 1.51460 49.96  7 57.13191.0000 1.72916 54.67  8 17.3739 8.0567  9 −39.1922 0.8000 1.61800 63.3910 23.7568 4.6135 1.90366 31.31 11 −350.6325 6.0068 12 −18.1546 0.80001.72916 54.67 13 −27.1337 0.2000 1.51460 49.96 14ASPH −27.1337 D(14)15STOP ∞ 1.0000 16 46.2428 0.8000 2.00100 29.13 17 24.6614 12.0000 1.49700 81.61 18 −18.2109 0.8000 1.72916 54.67 19 −43.1154 0.2000 2058.0584 3.1904 1.92286 20.88 21 312.8281 D(21) 22 62.1409 10.5808 1.59282 68.62 23 −28.1289 2.0754 2.00100 29.13 24 −40.9740 0.2000 2532.9464 0.8000 2.00100 29.13 26 16.2394 9.5000 1.56732 42.82 27−490.3985 7.1218 28ASPH 77.7354 0.2000 1.51460 49.96 29 70.5805 0.80001.48749 70.44 30 20.6466 D(30) 31 49.0278 6.4479 1.48749 70.44 32−59.3545 2.3878 33ASPH −25.2625 0.2000 1.51460 49.96 34 −30.0068 1.00001.72916 54.67 35 −96.0672 D(35) 36 ∞ 2.5000 1.51680 64.2 37 ∞ 1.0000

TABLE 17 No. K A4 A6 A8 A10  6 0.00000E+00   5.87977E−06 −1.03717E−09  9.16126E−11 −4.16372E−13   14 0.00000E+00 −6.54452E−07 −2.33693E−10−4.39359E−11 1.05431E−13 28 0.00000E+00 −2.67450E−06   2.95136E−08−1.25030E−10 6.99148E−13 33 0.00000E+00 1.26908E−05   1.44019E−08  2.61421E−11 0.00000E+00 No. A12 A14 A16 A18 A20  6 9.66541E−160.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 14 0.00000E+000.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 28 0.00000E+000.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 33 0.00000E+000.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00

TABLE 18 F 28.8550 46.3781 72.7963 Fno 2.9146 2.9039 2.9109 W 37.857225.2169 16.2227 D(5) 0.5000 8.3771 28.7168 D(14) 12.9226 4.5468 0.5000D(21) 4.2776 0.6209 0.5000 D(30) 4.3714 10.1862 11.4227 D(35) 18.079825.2443 28.6339

Example 7

(1) Configuration of Optical System

FIG. 25 is a cross-sectional view of a lens configuration example of azoom lens of Example 2 of the present invention. The zoom lens consistsof, in order from the object side, a first lens group G1 having positiverefractive power, a second lens group G2 having negative refractivepower, a third lens group G3 having positive refractive power, and afourth lens group G4 having positive refractive power, a fifth lensgroup G5 having negative refractive power, and a sixth lens group G6having negative refractive power, and changing focal length is performedby varying intervals between the lens groups. During changing focallength from the wide angle end to the telephoto end, the first lensgroup G1 to the sixth lens group G6 follow different paths to movetoward the object.

In the zoom lens of Example 7, the third lens group G3 to the sixth lensgroup G6 constitute a GR group of the present invention. The 17thsurface and the 18th surface included in the third lens group G3, andthe 23rd surface and the 26th surface included in the fourth lens groupG4 are cemented surfaces having negative refractive power in the presentinvention (see Table 19). In addition, in the third lens group G3, thelens closest to the image plane and having the 20th surface and the 21stsurface is a convex lens GpH in the present invention (see Table 19).Further, the lens, included in the third lens group, that has the 17thsurface and the 18th surface and constitutes a cemented lens; and thelens, included in the fourth lens group G4, that is closest to theobject in the group, constitutes a cemented lens, and has the 22ndsurface and the 23rd surface are convex lenses GpL in the presentinvention (see Table 19).

(2) Typical Numerical Values

Explanation will now be given of Typical numerical value 7 of the zoomlens to which specific numerical values are applied. Table 19 shows lensdata related to the zoom lens. For an aspherical surface, the asphericalfactor and the conic constant are shown in Table 20. Table 21 shows theF number (Fno) of the zoom lens having each focal length (F), the halfimage viewing angle (W), and the lens interval between movable groupwhich moves during changing focal length and the adjacent lens group onits image side. FIGS. 26 to 28 are longitudinal aberrations diagrams ofthe zoom lens at a time of focusing to infinity. Table 28 shows thefocal lengths (f1, f2, f3, f4, f5, and f6) of the respective lens groupsand the values in the conditional expressions (3) and (5). See Table 21for values related to the conditional expressions (1), (2) and (4), andsee Table 19 for values related to the conditional expression (6).

TABLE 19 No. R D Nd νd  1 89.8462 0.8000 1.84666 23.78  2 65.7289 5.91101.49700 81.61  3 337.6738 0.2000  4 63.8867 5.9429 1.49700 81.61  5458.7774 D(5)   6ASPH 53.9382 0.3000 1.51460 49.96  7 52.4590 1.00001.72916 54.67  8 15.3473 6.1341  9 −62.2260 0.8000 1.61997 63.88 1017.8218 4.6461 1.90366 31.31 11 245.0341 4.3861 12 −21.1314 0.80001.77250 49.62 13 −36.9762 0.2000 1.51460 49.96 14ASPH −36.9762 D(14)15STOP ∞ 1.0000 16 31.1637 0.8000 2.00100 29.13 17 17.6184 5.17031.49700 81.61 18 −15.1437 0.8000 1.72916 54.67 19 −47.2908 0.2761 2030.6800 3.7217 1.85478 24.80 21 88.7917 D(21) 22 116.7715 4.0481 1.5928268.62 23 −23.3030 1.0485 2.00100 29.13 24 −32.3897 0.3542 25 31.12080.9753 1.95375 32.32 26 12.8043 6.3245 1.59551 39.24 27 −135.6473 D(27)28ASPH −9476.2911 0.2000 1.51460 49.96 29 7238.2422 0.8000 1.48749 70.4430 23.0902 D(30) 31 108.9978 3.8111 1.51742 52.15 32 −47.6477 9.825333ASPH −19.1540 0.2000 1.51460 49.96 34 −20.9407 1.0000 1.72916 54.67 35−45.9597 D(35) 36 ∞ 2.5000 1.51680 64.20 37 ∞ 1.0000

TABLE 20 No. K A4 A6 A8 A10  6 0.00000E+00   2.42293E−06 1.01618E−093.21453E−11 −1.80773E−13   14 0.00000E+00 −1.86827E−06 −6.67448E−09  1.03911E−11 2.23944E−13 28 0.00000E+00 −4.07547E−07 5.40812E−081.30501E−11 2.53614E−12 33 0.00000E+00   2.05763E−05 2.03013E−081.13308E−10 0.00000E+00 No. A12 A14 A16 A18 A20  6 5.64248E−160.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 14 0.00000E+000.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 28 0.00000E+000.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 33 0.00000E+000.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00

TABLE 21 F 28.8538 58.2943 131.0500 Fno 3.8576 4.9761 6.4925 W 37.890019.9211 9.1924 D(5) 0.5000 18.2070 39.7386 D(14) 17.8824 8.3315 0.5000D(21) 5.0323 2.2114 1.9791 D(27) 5.4553 5.4553 5.4553 D(30) 3.689512.1563 18.9384 D(35) 14.4999 22.1976 33.4008

Example 8

(1) Configuration of Optical System

FIG. 29 is a cross-sectional view of a lens configuration example of azoom lens of Example 8 of the present invention. The zoom lens consistsof, in order from the object side, a first lens group G1 having positiverefractive power, a second lens group G2 having negative refractivepower, a third lens group G3 having positive refractive power, and afourth lens group G4 having positive refractive power, a fifth lensgroup G5 having negative refractive power, and a sixth lens group G6having negative refractive power, and changing focal length is performedby varying intervals between the lens groups. During changing focallength from the wide angle end to the telephoto end, the first lensgroup G1 to the sixth lens group G6 follow different paths to movetoward the object.

In the zoom lens of Example 8, the third lens group G3 to the sixth lensgroup G6 constitute a GR group of the present invention. The 17thsurface and the 18th surface included in the third lens group G3, andthe 23rd surface and the 26th surface included in the fourth lens groupG4 are cemented surfaces having negative refractive power in the presentinvention (see Table 22). In addition, in the third lens group G3, thelens closest to the image plane and having the 20th surface and the 21stsurface is a convex lens GpH in the present invention (see Table 22).Further, the lens, included in the third lens group, that has the 17thsurface and the 18th surface and constitutes a cemented lens; and thelens, included in the fourth lens group G4, that is closest to theobject in the group, constitutes a cemented lens, and has the 22ndsurface and the 23rd surface are convex lenses GpL in the presentinvention (see Table 22).

(2) Typical Numerical Values

Explanation will now be given of Typical numerical value 8 of the zoomlens to which specific numerical values are applied. Table 22 shows lensdata related to the zoom lens. For an aspherical surface, the asphericalfactor and the conic constant are shown in Table 23. Table 24 shows theF number (Fno) of the zoom lens having each focal length (F), the halfimage viewing angle (W), and the lens interval between movable groupwhich moves during changing focal length and the adjacent lens group onits image side. FIGS. 30 to 32 are longitudinal aberrations diagrams ofthe zoom lens at a time of focusing to infinity. Table 28 shows thefocal lengths (f1, f2, f3, f4, f5, and f6) of the respective lens groupsand the values in the conditional expressions (3) and (5). See Table 22for values related to the conditional expressions (1), (2) and (4), andsee Table 24 for values related to the conditional expression (6).

TABLE 22 No. R D Nd νd  1 84.0016 0.8000 2.00100 29.13  2 61.5145 7.98231.49700 81.61  3 23320.6300 0.2000  4 60.6167 6.1743 1.49700 81.61  5297.8443 D(5)   6ASPH 87.9229 0.3000 1.51460 49.96  7 89.4256 1.00001.72916 54.67  8 16.1434 5.1949  9 −79.1628 0.8000 1.72916 54.67 1016.8728 5.4251 1.85026 32.27 11 −106.3715 2.5199 12 −20.8969 0.80001.72916 54.67 13 −43.5829 0.2000 1.51460 49.96 14ASPH −43.5829 D(14)15STOP ∞ 1.0000 16 28.2560 0.8014 1.95375 32.32 17 16.0508 5.44481.49700 81.61 18 −15.1221 0.8000 1.72916 54.67 19 −50.5731 0.1999 2026.0822 3.9080 1.85478 24.80 21 55.7794 D(21) 22 79.1543 4.5529 1.4970081.61 23 −19.5554 0.8000 1.88100 40.14 24 −26.8748 0.2000 25 33.21680.9118 2.00100 29.13 26 12.3234 5.9647 1.62004 36.30 27 −151.5275 D(27)28ASPH 345.2373 0.2000 1.51460 49.96 29 384.5543 0.8000 1.49700 81.61 3023.7273 D(30) 31 101.4632 4.4181 1.54072 47.20 32 −40.2031 8.0951 33ASPH−17.6762 0.2000 1.51460 49.96 34 −21.1807 1.0000 1.48749 70.44 35−249.7905 D(35) 36 ∞ 2.5000 1.51680 64.20 37 ∞ 1.0000

TABLE 23 No. K A4 A6 A8 A10  6 0.00000E+00 1.36961E−06 4.46352E−091.22928E−11 −1.36605E−13   14 0.00000E+00 −1.01455E−05   −1.79636E−09  −7.09159E−12   4.34280E−13 28 0.00000E+00 2.09519E−07 1.46615E−082.65729E−10 1.92250E−12 33 0.00000E+00 2.43612E−05 2.43784E−081.91482E−10 0.00000E+00 No. A12 A14 A16 A18 A20  6 6.05277E−160.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 14 0.00000E+000.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 28 0.00000E+000.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 33 0.00000E+000.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00

TABLE 24 F 28.8657 58.2285 193.9232 Fno 3.8225 4.9891 6.5351 W 37.942119.7325 6.2386 D(5) 0.5000 16.7096 48.7180 D(14) 20.6052 10.3273 0.5000D(21) 4.1332 1.6019 0.5000 D(27) 7.2400 8.1893 1.9552 D(30) 2.963410.3456 24.9615 D(35) 14.4998 20.7471 34.1722

Example 9

(1) Configuration of Optical System

FIG. 33 is a cross-sectional view of a lens configuration example of azoom lens of Example 9 of the present invention. The zoom lens consistsof, in order from the object side, a first lens group G1 having positiverefractive power, a second lens group G2 having negative refractivepower, a third lens group G3 having positive refractive power, and afourth lens group G4 having positive refractive power, a fifth lensgroup G5 having negative refractive power, and a sixth lens group G6having negative refractive power, and changing focal length is performedby varying intervals between the lens groups. During changing focallength from the wide angle end to the telephoto end, the first lensgroup G1 to the sixth lens group G6 follow different paths to movetoward the object.

In the zoom lens of Example 9, the third lens group G3 to the sixth lensgroup G6 constitute a GR group of the present invention. The 17thsurface and the 18th surface included in the third lens group G3, andthe 23rd surface and the 26th surface included in the fourth lens groupG4 are cemented surfaces having negative refractive power in the presentinvention (see Table 25). In addition, in the third lens group G3, thelens closest to the image plane and having the 20th surface and the 21stsurface is a convex lens GpH in the present invention (see Table 25).Further, the lens, included in the third lens group, that has the 17thsurface and the 18th surface and constitutes a cemented lens; and thelens, included in the fourth lens group G4, that is closest to theobject in the group, constitutes a cemented lens, and has the 22ndsurface and the 23rd surface are convex lenses GpL in the presentinvention (see Table 25).

(2) Typical Numerical Values

Explanation will now be given of Typical numerical value 9 of the zoomlens to which specific numerical values are applied. Table 25 shows lensdata related to the zoom lens. For an aspherical surface, the asphericalfactor and the conic constant are shown in Table 26. Table 27 shows theF number (Fno) of the zoom lens having each focal length (F), the halfimage viewing angle (W), and the lens interval between movable groupwhich moves during changing focal length and the adjacent lens group onits image side. FIGS. 33 to 36 are longitudinal aberrations diagrams ofthe zoom lens at a time of focusing to infinity. Table 28 shows thefocal lengths (f1, f2, f3, f4, f5, and f6) of the respective lens groupsand the values in the conditional expressions (3) and (5). See Table 25for values related to the conditional expressions (1), (2) and (4), andsee Table 27 for values related to the conditional expression (6).

TABLE 25 No. R D Nd νd  1 100.4579 0.8000 1.95375 32.32  2 66.86597.3416 1.49700 81.61  3 −1666.2433 0.2000  4 65.8322 5.9217 1.4970081.61  5 394.4123 D(5)   6ASPH 69.4585 0.3000 1.51460 49.96  7 73.46281.0000 1.77250 49.62  8 16.4815 5.4291  9 −93.7897 0.9783 1.72916 54.6710 16.2161 5.6605 1.85026 32.27 11 −100.1948 2.6676 12 −21.6951 0.80001.72916 54.67 13 −51.0141 0.2000 1.51460 49.96 14ASPH −51.0141 D(14)15STOP ∞ 1.0000 16 29.8573 1.7947 1.95375 32.32 17 16.1176 5.96061.49700 81.61 18 −15.4872 0.8000 1.72916 54.67 19 −47.3489 0.2000 2024.9365 3.9724 1.85478 24.80 21 52.7373 D(21) 22 130.4876 4.6774 1.5168064.20 23 −19.0049 0.8000 1.90366 31.31 24 −26.5862 0.2000 25 36.49560.8000 2.00100 29.13 26 12.7731 6.1377 1.62004 36.30 27 −115.2758 D(27)28ASPH 149.0328 0.2000 1.51460 49.96 29 146.8651 0.8000 1.49700 81.61 3022.5604 D(30) 31 88.9830 4.4880 1.59551 39.24 32 −37.9873 5.5139 33ASPH−17.5192 0.2000 1.51460 49.96 34 −20.0556 1.0000 1.72916 54.67 35−98.4064 D(35) 36 ∞ 2.5000 1.51680 64.20 37 ∞ 1.0000

TABLE 26 No. K A4 A6 A8 A10  6 0.00000E+00 −1.12030E−07 −9.06727E−105.27511E−11 −3.01346E−13   14 0.00000E+00 −1.02028E−05   1.27579E−09−3.94385E−11   3.62949E−13 28 0.00000E+00   3.02125E−06 −9.74046E−092.70498E−10 9.53230E−13 33 0.00000E+00   3.16820E−05   3.45788E−081.99525E−10 0.00000E+00 No. A12 A14 A16 A18 A20  6 7.51711E−160.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 14 0.00000E+000.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 28 0.00000E+000.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 33 0.00000E+000.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00

TABLE 27 F 28.8650 58.2341 242.4539 Fno 3.6420 4.9282 6.4024 W 37.941819.7741 5.0047 D(5) 0.5000 16.0823 61.0487 D(14) 22.1569 10.7578 0.5000D(21) 3.8590 1.4413 0.5000 D(27) 10.2726 11.9414 1.9680 D(30) 3.032210.0530 26.2569 D(35) 14.4998 21.1339 36.3829

TABLE 28 Example Example Example Example Example Example Example ExampleExample 1 2 3 4 5 6 7 8 9 f1 120.38 131.03 122.35 127.87 122.18 108.39107.71 98.18 108.54 f2 −19.11 −19.55 −19.83 −20.32 −18.20 −19.80 −19.25−18.90 −19.69 f3 65.21 58.72 68.74 65.42 76.53 54.35 44.49 43.60 42.57f4 53.50 58.24 54.38 56.83 47.21 73.38 38.98 43.63 48.24 f5 — — — — —−2567.68 −47.23 −51.33 −53.63 f6 — — — — — — −467.68 −331.97 −168.17hGpH/hStop 1.29 1.26 1.19 1.18 1.30 1.34 1.17 1.15 1.14 f1/fw 4.17 4.544.24 4.43 4.93 3.76 3.73 3.40 3.76

Consequently, the present invention can provide a large-aperture zoomlens that can perform favorable correction of chromatic aberration inthe entire zoom range, and an imaging apparatus including the zoom lens.

What is claimed is:
 1. A zoom lens comprising, in order from an objectside: a first lens group having positive refractive power; a second lensgroup having negative refractive power; and a GR group including one ormore lens groups, wherein changing focal length is performed by varyingintervals between the lens groups, and wherein the GR group includes oneor more convex lens GpH satisfying the following conditional expression(1), and one or more convex lens GpL satisfying the followingconditional expression (2), and the convex lens GpH is the positivelens, which is arranged second position or after from the object side inpositive lenses included in the GR group:1.85<ndpH<2.50  (1)60.0<vdpL<100.0  (2) wherein ndpH is a refractive index related to ad-line of the convex lens GpH, and vdpL is an Abbe constant related to ad-line of the convex lens GpL and wherein the following conditionalexpression is satisfied:1.00<hGpH/hStop<2.00  (3) wherein hGpH is a maximum height from anoptical axis when on-axis luminous passes through a surface of theconvex lens GpH on the object side, at the telephoto end of the zoomlens, and hStop is a maximum height from an optical axis when on-axisluminous passes through an aperture stop, at the telephoto end of thezoom lens.
 2. The zoom lens according to claim 1, wherein the GR groupcomprises at least two cemented surfaces having negative refractivepower.
 3. The zoom lens according to claim 1, wherein the convex lensGpH satisfies the following conditional expression:10.0<vdpH<35.0  (4) wherein vdpH is an Abbe constant related to a d-lineof the convex lens GpH.
 4. The zoom lens according to claim 1, whereinthe GR group includes one or more lens group having positive refractivepower, and the convex lens GpH is arranged in the lens group havingpositive refractive power.
 5. The zoom lens according to claim 1,wherein the following conditional expression is satisfied:0.90<fl/fw<15.00  (5) wherein fl is a focal length of the first lensgroup, and fw is a focal length of the zoom lens at the wide angle end.6. The zoom lens according to claim 1, wherein the GR group includes atleast two of the convex lens GpL.
 7. The zoom lens according to claim 1,wherein the following conditional expression is satisfied:0.95<Fno_t<5.60  (6) wherein Fno_t is an F number of the zoom lens atthe telephoto end.
 8. An imaging apparatus, comprising: a zoom lensaccording to claim 1; and an imaging device arranged on the image sideof the zoom lens and configured to convert an optical image formed bythe zoom lens to electrical signals.